Sequential closing of electric vehicle power supply equipment contactors

Abstract

The invention provides sequential closing of electric vehicle supply equipment contactors. The electric vehicle power supply apparatus may include a pair of parallel contactors electrically connecting the vehicle with a power source. The electric vehicle power supply apparatus also includes a controller that closes one of the pair of contactors before the other of the pair of contactors is closed based on cumulative exposure in the surge current of each of the pair of contactors.

Description

Technical Field

[0001] The present disclosure relates to operating electric vehicle supply equipment (EVSE) to provide electrical energy to a vehicle. Background Art

[0002] Electric vehicles may rely on one or more traction batteries to provide electrical energy to the motor for propulsion. The traction batteries may be recharged by a power source through the EVSE. Summary of the invention

[0003] A vehicle charging system has an electric vehicle supply device, the electric vehicle supply device including: a pair of contactors that electrically connect the vehicle to a power source; and a controller that closes one of the pair of contactors before the other of the pair of contactors closes based on cumulative exposure to inrush current in each of the pair of contactors.

[0004] A method includes, after connecting an electric vehicle supply equipment to a vehicle, sequentially closing a pair of parallel contactors electrically connecting the vehicle to a power source such that a last contactor of the pair of contactors to be closed is closed based on a zero voltage crossing of power associated with the power source, and a first contactor of the pair of contactors to be closed is not closed based on the zero voltage crossing of the power.

[0005] The electric vehicle supply equipment has a charging line including a pair of contactors and a controller. After the charging line has been connected to the vehicle, the controller sequentially closes the pair of contactors so that a first contactor of the pair of contactors to be closed is closed based on a cumulative exposure to inrush current of each of the pair of contactors and a second contactor of the pair of contactors to be closed is closed based on a zero voltage crossing of power associated with a power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 An example block topology of an electrified vehicle having a powertrain and energy storage components is shown.

[0007] Figure 2 An example block diagram of an EVSE with a high voltage bus and contactors is shown.

[0008] Figure 3 An example flow chart of a process for operating an EVSE to charge a vehicle is shown. DETAILED DESCRIPTION

[0009] Embodiments are described herein. However, it should be understood that the disclosed embodiments are merely examples and that other embodiments may take various and alternative forms. The drawings are not necessarily drawn to scale. Some features may be enlarged or minimized to show details of particular components. Therefore, the specific structural details and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art.

[0010] The various features shown and described with reference to any one of the accompanying drawings may be combined with features shown in one or more other drawings to produce embodiments not explicitly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, for specific applications or implementations, various combinations and modifications of features consistent with the teachings of the present disclosure may be desired.

[0011] The present disclosure proposes, among other things, a system and method for controlling an EVSE to charge an electric vehicle.

[0012] Figure 1 A plug-in hybrid electric vehicle (PHEV) is shown. The plug-in hybrid electric vehicle 112 may include one or more motors (electric motors) 114 mechanically coupled to a hybrid transmission 116. The motor 114 may be capable of operating as a motor or a generator. In addition, the hybrid transmission 116 is mechanically coupled to an engine 118. The hybrid transmission 116 is also mechanically coupled to a drive shaft 120, which is mechanically coupled to wheels 122. The motor 114 can provide propulsion and braking capabilities when the engine 118 is turned on or off. The motor 114 can also act as a generator and can provide fuel economy benefits by recovering energy lost as heat in the friction braking system. The motor 114 can also reduce vehicle emissions by allowing the engine 118 to operate at a more efficient speed and allowing the hybrid electric vehicle 112 to be operated in an electric mode when the engine 118 is turned off under certain conditions.

[0013] The traction battery or battery pack 124 stores energy that can be used by the motor 114. The vehicle battery pack 124 can provide a high voltage DC output. The traction battery 124 can be electrically coupled to one or more battery electric control modules (BECM) 125. The BECM 125 can be provided with one or more processors and software applications configured to monitor and control various operations of the traction battery 124. The traction battery 124 can also be electrically coupled to one or more power electronics modules 126. The power electronics module 126 can also be referred to as a power inverter. One or more contactors 127 can isolate the traction battery 124 and the BECM 125 from other components when open, and connect the traction battery 124 and the BECM 125 to other components when closed. The power electronics module 126 can also be electrically coupled to the motor 114 and provide the ability to transfer energy bidirectionally between the traction battery 124 and the motor 114. For example, the traction battery 124 can provide a DC voltage, and the motor 114 can operate using a three-phase AC current. The power electronics module 126 may convert the DC voltage into a three-phase AC current for use by the motor 114. In regenerative mode, the power electronics module 126 may convert the three-phase AC current from the motor 114 acting as a generator into a DC voltage compatible with the traction battery 124. The description herein is equally applicable to pure electric vehicles. For pure electric vehicles, the hybrid transmission 116 may be a gearbox connected to the motor 114 and the engine 118 may not be present.

[0014] In addition to providing energy for propulsion, the traction battery 124 can also provide energy for other vehicle electrical systems. The vehicle includes a DC / DC converter module 128 that converts the high voltage DC output of the traction battery 124 to a low voltage DC supply that is compatible with other low voltage vehicle loads. The output of the DC / DC converter module 128 can be electrically coupled to an auxiliary battery 130 (e.g., a 12V battery).

[0015] The vehicle 112 may be a battery electric vehicle (BEV) or a plug-in hybrid electric vehicle (PHEV), wherein the traction battery 124 may be recharged by an external power source 136. The external power source 136 may be a connection to an electrical outlet. The external power source 136 may be a distribution network or grid provided by an electric utility company. The external power source 136 may be electrically coupled to an electric vehicle supply equipment (EVSE) 138. The EVSE 138 may provide circuits and controls to manage energy transfer between the power source 136 and the vehicle 112. The external power source 136 may provide DC or AC power to the EVSE 138. The EVSE 138 may have a charging connector 140 for plugging into a charging port 134 of the vehicle 112. The charging port 134 may be any type of port configured to transfer power from the EVSE 138 to the vehicle 112. The charging port 134 may be electrically coupled to a charger or an onboard power conversion module 132. The power conversion module 132 may condition the power supplied from the EVSE 138 to provide the appropriate voltage and current levels to the traction battery 124. The power conversion module 132 may interact with the EVSE 138 to coordinate the delivery of power to the vehicle 112. The EVSE connector 140 may have pins that mate with corresponding recesses of the charging port 134. Alternatively, the various components described as being electrically coupled may transfer power using wireless inductive coupling.

[0016] One or more electrical loads 146 may be coupled to the high voltage bus. The electrical loads 146 may have associated controllers that operate and control the electrical loads 146 as appropriate. Examples of electrical loads 146 may be heating modules, air conditioning modules, and the like.

[0017] The various components discussed may have one or more associated controllers to control and monitor the operation of the components. The controllers may communicate via a serial bus (e.g., a controller area network (CAN)) or via discrete conductors. A system controller 150 may be present to coordinate the operation of the various components. It should be noted that the system controller 150 is used as a general term and may include one or more controller devices configured to perform various operations in the present disclosure. For example, the system controller 150 may be programmed to enable powertrain control functions to operate the powertrain of the vehicle 112. The system controller 150 may also be programmed to implement telecommunication functions with various entities (e.g., servers) via a wireless network (e.g., a cellular network).

[0018] The system controller 150 and / or the BECM 125 may be programmed, individually or in combination, to perform various operations with respect to the traction battery 124. For example, the system controller 150 and / or the BECM 125 may be configured to communicate with the EVSE 138 to operate and facilitate the battery charging process. Figure 2, shows an example block diagram of the EVSE 138 and a portion of the EVSE circuit. Figure 1 , the EVSE 138 may be configured to receive AC current from the power source 136 on the power source side. The EVSE 138 may also be configured to output AC current to the vehicle 112 on the vehicle side. A positive high voltage (HV) bus 202a and a negative HV bus 202b may be connected between the power source side and the vehicle side of the EVSE circuit and configured to transfer electrical energy between the power source 136 and the vehicle 112. In one example, the positive HV bus 202a and the negative HV bus 202b may be directly connected between the power source side and the vehicle side so that the AC current received from the power source 136 and the AC current output to the vehicle 112 are associated with the same properties (e.g., voltage, frequency, etc.). Alternatively, if the AC current output to the vehicle 112 has different properties than the AC current received from the power source, additional circuitry (not shown) may be provided to the EVSE 138 to facilitate power conversion. In the present disclosure, positive main contactor MC+ 204a may be disposed on positive HV bus 202a, and negative main contactor MC- 204b may be disposed on negative HV bus 202b. Main contactors 204a and 204b may be selectively opened and closed to connect the power supply side and the vehicle side of EVSE 138.

[0019] The operation of the main contactors 204a and 204b may be controlled by the EVSE controller 206. The EVSE controller 206 may be configured to control the opening and closing of the main contactors 204a and 204b based on various factors obtained from the vehicle 112 and the power source 136. For example, the EVSE 138 may be provided with a communication capability to communicate with the vehicle 112 and receive information about the condition of the traction battery 124 (e.g., battery SOC, temperature). As discussed above, the system controller 150 and BECM 125 of the vehicle 112 may communicate with the EVSE 138 and provide information about the traction battery 124 to facilitate vehicle charging. In response to detecting that the EVSE connector 140 is coupled to the vehicle 112, data communication may be established between the EVSE 138 and the vehicle 112 to prepare for charging. The controller 206 may start the charging process by closing both the main contactors 204a and 204b. One method is to sequentially close the main contactors 204a and 204b with a short period of time between them. For example, the positive main contactor 204a may be closed first, and the negative main contactor 204b may be closed subsequently. In this example, the power source 136 is not connected to the vehicle 112 until the negative (i.e., subsequent) main contactor 204b is closed. The EVSE controller 206 may exchange the closing sequence between the positive main contactor 204a and the negative main contactor 204b so that the contacts may have an even wear condition.

[0020] As discussed above, AC current is supplied to the vehicle 112 to charge the traction battery 124. The AC current on the positive HV bus 204a and the negative HV bus 204b may be in the form of a sine wave, as shown in the waveform diagram 210. To further minimize the effects of the inrush current, the controller 206 may be configured to operate the main contactors 204a and 204b to close at the zero voltage crossing point 212, as shown in the waveform diagram 210. Alternatively, since the charging circuit is incomplete and therefore no inrush current occurs when only the first main contactor is closed, the first contactor may be closed at any time regardless of the phase of the waveform. The EVSE controller 206 may be configured to only command the subsequent main contactor to close at the zero voltage crossing point 212 to mitigate the inrush current. Despite efforts to mitigate the inrush current, the timing of closing the second main contactor may not be 100% accurate due to various factors. Once the charging circuit is closed when the subsequent main contactor is closed, a small amount of inrush current may still be generated. The EVSE 138 may also be provided with one or more current sensors 214 to monitor the current on the positive HV bus 202 a and the negative HV bus 202 b .

[0021] refer to Figure 3 , shows an example flow chart of a process 300 for operating an EVSE. Figure 1 and Figure 2, the process 300 may be implemented via the EVSE controller 206. At operation 302, in response to detecting that the vehicle 112 has been connected to the EVSE 138 via the connector 140, the EVSE controller 206 establishes a data communication link with the vehicle 112. As discussed above, the EVSE controller 206 may be configured to communicate with the system controller 150 and the BECM 125 via the EVSE connector 140, which is configured to support a data communication protocol. Additionally or alternatively, one or more wireless communication links (e.g., Wi-Fi) may be established between the EVSE 138 and the vehicle 112 to enable data communication. At operation 304, the EVSE controller 206 receives vehicle information related to battery charging from the vehicle 112. The vehicle information may include various entries that may be used to operate the EVSE 138 to control the battery charging process. For example, the vehicle information may include a current SOC, which is used as a starting SOC for charging the traction battery 124. In general, a lower starting SOC (e.g., 20%) may be associated with a higher starting charging power, and thus may be associated with a higher inrush current when the second main contactor 204 is closed. In contrast, a higher starting SOC (e.g., 70%) may be associated with a lower starting charging power, and thus may be associated with a lower inrush current. The vehicle information may also include the temperature of the traction battery 124 measured by a temperature sensor (not shown). The vehicle information may also include the battery and charging configuration (e.g., voltage, power limit) associated with the traction battery 124. Upon receiving the vehicle information, the EVSE controller 206 adjusts settings accordingly to prepare for the charging process.

[0022] At operation 306, the EVSE 206 operates one of the main contactors 204 with a lower life (larger cumulative exposure in the inrush current) to close, so that one of the positive HV bus 202a or the negative HV bus 202b is connected between the power supply side and the vehicle side. Then at operation 308, the EVSE controller 206 operates another main contactor with a higher life (e.g., better condition) to close, so that the charging circuit is activated to start charging the traction battery 124. Depending on the usage history, the positive main contactor 204a and the negative main contactor 204b can be associated with different life / conditions. For example, a main contactor 204 that is subjected to more frequent and higher magnitude inrush currents may be associated with a lower life compared to another main contactor 204 that is subjected to less frequent and lower magnitude inrush currents. The life / condition of each main contactor can be evaluated based on various factors (to be discussed below) and recorded in a memory accessible by the EVSE controller 206. Since the charging circuit is not activated before the second main contactor is closed, the first main contactor to be closed will have a shorter life than the second main contactor to be closed. Therefore, a more even life shared between the two main contactors 204 can be achieved.

[0023] At operation 310, the EVSE controller 206 measures the inrush current generated by the closing of the second main contactor via one of the current sensors 214. As discussed above, ideally, the inrush current should be zero because the controller 206 commands the second main contactor 204 to close at the zero voltage crossing point. However, the timing control of closing the second main contactor 204 at the zero voltage crossing may not be completely accurate, and a small amount of inrush current may be generated. At operation 312, the EVSE controller 206 evaluates the impact of the inrush current on the life depreciation of the second main contactor and updates the life properties associated with the second main contactor. The life depreciation of the second main contactor 204 can be quantified and evaluated in various ways. For example, a higher inrush current (e.g., 10A) can be evaluated as an equivalent that results in a higher life depreciation (e.g., 0.1%), while a lower inrush current (e.g., 2A) can be evaluated as an equivalent that results in a lower life depreciation (e.g., 0.02%). The EVSE 206 records the updated life properties of the second main contactor 204 in memory. When the next vehicle charging begins, the EVSE 206 determines a sequence for closing the main contactors 204 based on the updated life properties of the two main contactors.

[0024] In addition to using measured inrush current, there are alternative methods to assess the depreciation of the main contactor. For example, in addition to or in lieu of the inrush current measured by the current sensor 214, the EVSE controller 206 may be configured to assess the lifetime depreciation of the main contactor 204 based on the starting SOC of the traction battery 124. In general, a lower starting SOC of the traction battery 124 may be associated with a higher amount of inrush current, and a higher starting SOC of the traction battery 124 may be associated with a lower amount of inrush current. Thus, a lower starting SOC may be assessed as resulting in an equivalent amount of higher lifetime depreciation, and a higher starting SOC may be assessed as resulting in an equivalent amount of lower lifetime depreciation.

[0025] Additionally or alternatively, the EVSE 206 may also be configured to swap the closing sequence of the main contactors whenever a new charging process begins, regardless of the inrush current or starting SOC.

[0026] The algorithm, method or process disclosed herein can be delivered to or implemented by a computer, a controller or a processing device, and the computer, the controller or the processing device can include any dedicated electronic control unit or a programmable electronic control unit. Similarly, the algorithm, method or process can be stored in various forms as data and instructions that can be executed by a computer or a controller, including but not limited to information permanently stored on a non-writable storage medium such as a read-only memory device and information that can be changed and stored on a writable storage medium such as an optical disk, a random access memory device or other magnetic and optical media. The algorithm, method or process can also be implemented by a software executable object. Alternatively, the algorithm, method or process can be implemented in whole or in part using a combination of suitable hardware components (such as an application-specific integrated circuit, a field programmable gate array, a state machine or other hardware components or devices) or firmware, hardware and software components.

[0027] Although exemplary embodiments are described above, these embodiments are not intended to describe all possible forms covered by the claims. The words used in the specification are descriptive rather than limiting, and it should be understood that various changes can be made without departing from the spirit and scope of the present disclosure. The words "a processor" and "multiple processors" are interchangeable herein, as are the words "a controller" and "multiple controllers".

[0028] As previously described, the features of the various embodiments may be combined to form additional embodiments of the invention that may not be explicitly described or shown. Although various embodiments may have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, it will be appreciated by those of ordinary skill in the art that one or more features or characteristics may be compromised to achieve desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, strength, durability, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, and the like. Thus, embodiments described as being less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of this disclosure and may be desirable for a particular application.

[0029] According to the present invention, a vehicle charging system is provided, the vehicle charging system having: an electric vehicle power supply device, the electric vehicle power supply device including: a pair of contactors, the pair of contactors being configured to electrically connect a vehicle to a power source; and a controller programmed to close one of the pair of contactors before the other of the pair of contactors is closed based on the cumulative exposure to inrush current of each of the pair of contactors.

[0030] According to one embodiment, the controller is further programmed to close the other of the pair of contactors based on a zero voltage crossing of power associated with the power source.

[0031] According to one embodiment, the cumulative exposure to inrush current of one of the pair of contactors is greater than the cumulative exposure to inrush current of the other of the pair of contactors.

[0032] According to one embodiment, the controller is further programmed to update a parameter indicative of cumulative exposure in inrush current of one of the pair of contactors, or to update a parameter indicative of cumulative exposure in inrush current of the other of the pair of contactors.

[0033] According to one embodiment, the controller is further programmed to close one of the pair of contactors before the other of the pair of contactors is closed in response to a request to charge the vehicle.

[0034] According to one embodiment, the pair of contactors are connected in parallel.

[0035] According to the present invention, a method includes: after connecting an electric vehicle supply equipment to a vehicle, sequentially closing a pair of parallel contactors configured to electrically connect the vehicle to a power source, so that a last contactor to be closed in the pair of contactors is closed based on a zero voltage crossing of power associated with the power source, and a first contactor to be closed in the pair of contactors is not closed based on the zero voltage crossing of the power.

[0036] In one aspect of the invention, the method includes closing a first contactor of the pair of contactors based on cumulative exposure of the first contactor of the pair of contactors to an inrush current.

[0037] In one aspect of the invention, the cumulative exposure to inrush current of a first contactor of the pair of contactors is greater than the cumulative exposure to inrush current of a last contactor of the pair of contactors.

[0038] In one aspect of the invention, the method comprises updating a parameter indicative of a cumulative exposure to inrush current of a first contactor of the pair of contactors, or updating a parameter indicative of an exposure to inrush current of a last contactor of the pair of contactors.

[0039] In one aspect of the invention, the sequential closing is in response to a request to charge the vehicle.

[0040] According to the present invention, an electric vehicle supply equipment is provided, the electric vehicle supply equipment having: a charging line including a pair of contactors; and a controller, the controller being programmed to: after the charging line has been connected to the vehicle, sequentially close the pair of contactors so that a first contactor of the pair of contactors to be closed is closed based on a cumulative exposure to an inrush current of each of the pair of contactors, and a second contactor of the pair of contactors to be closed is closed based on a zero voltage crossing of power associated with a power grid.

[0041] According to one embodiment, the cumulative exposure to inrush current of a first contactor of the pair of contactors is greater than the cumulative exposure to inrush current of a second contactor of the pair of contactors.

[0042] According to one embodiment, the controller is further programmed to update a parameter indicative of cumulative exposure to inrush current of a first contactor of the pair of contactors, or to update a parameter indicative of cumulative exposure to inrush current of a second contactor of the pair of contactors.

[0043] According to one embodiment, the controller is further programmed to sequentially close the pair of contactors in response to a request to charge the vehicle.

[0044] According to one embodiment, the pair of contactors are connected in parallel.

Claims

1. A vehicle charging system, comprising: An electric vehicle supply device comprising: a pair of contactors configured to electrically connect a vehicle to a power source; and a controller programmed to close one of the pair of contactors before the other of the pair of contactors closes based on cumulative exposure to inrush current in each of the pair of contactors.

2. The vehicle charging system of claim 1, wherein the controller is further programmed to close the other of the pair of contactors based on a zero voltage crossing of power associated with the power source. 3 . The vehicle charging system of claim 1 , wherein the cumulative exposure to inrush current of the one of the pair of contactors is greater than the cumulative exposure to inrush current of the other of the pair of contactors.

4. The vehicle charging system of claim 1 , wherein the controller is further programmed to update a parameter indicative of the cumulative exposure in inrush current of the one of the pair of contactors and to update a parameter indicative of the cumulative exposure in inrush current of the other of the pair of contactors.

5. The vehicle charging system of claim 1, wherein the controller is further programmed to close the one of the pair of contactors before the other of the pair of contactors closes in response to a request to charge the vehicle.

6. The vehicle charging system of claim 1, wherein the pair of contactors are connected in parallel.

7. A method comprising: After connecting the electric vehicle supply equipment to the vehicle, a pair of parallel contactors configured to electrically connect the vehicle to a power source are closed in sequence such that a last contactor of the pair of contactors to be closed is closed based on a zero voltage crossing of power associated with the power source, and a first contactor of the pair of contactors to be closed is not closed based on the zero voltage crossing of the power. 8 . The method of claim 7 , further comprising closing the first of the pair of contactors based on cumulative exposure to inrush current of the first of the pair of contactors.

9. The method of claim 8, wherein the cumulative exposure to inrush current of the first contactor of the pair of contactors is greater than the cumulative exposure to inrush current of the last contactor of the pair of contactors.

10. The method of claim 8, further comprising updating a parameter indicative of the cumulative exposure to inrush current of the first contactor of the pair of contactors, and updating a parameter indicative of the exposure to inrush current of the last contactor of the pair of contactors.

11. The method of claim 8, wherein the sequential closing is in response to a request to charge the vehicle.

12. An electric vehicle power supply device, comprising: a charging circuit, the charging circuit comprising a pair of contactors; as well as a controller programmed to, after the charging cord has been connected to the vehicle, sequentially close the pair of contactors such that a first one of the pair of contactors to be closed is closed based on a cumulative exposure to inrush current of each of the pair of contactors and a second one of the pair of contactors to be closed is closed based on a zero voltage crossing of power associated with a grid.

13. The electric vehicle supply equipment of claim 12, wherein the cumulative exposure to inrush current of the first of the pair of contactors is greater than the cumulative exposure to inrush current of the second of the pair of contactors.

14. The electric vehicle supply equipment of claim 12, wherein the controller is further programmed to update a parameter indicative of the cumulative exposure in inrush current of the first contactor of the pair of contactors, and to update a parameter indicative of the cumulative exposure in inrush current of the second contactor of the pair of contactors.

15. The electric vehicle supply equipment of claim 12, wherein the controller is further programmed to sequentially close the pair of contactors in response to a request to charge the vehicle.

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